Posted
by
kdawson
on Tuesday March 16, 2010 @11:00PM
from the brittania-waives-the-rules dept.

It's been a longtimecoming (2007, 2005, and 2002 respectively), but the project to harness wave energy off the Scots coast is finally coming together. Reader krou writes: "The BBC is reporting that ten sites on the seabed off Scotland in Pentland Firth and around Orkney have been leased to energy companies with the hopes of generating wave and tidal energy. 'Six sites have been allocated for wave energy developments potentially generating 600 megawatts of power and four for tidal projects, also generating 600 MW.' The leases were awarded to SSE Renewables Developments, Aquamarine Power, ScottishPower Renewables, E.ON, Pelamis Wave Power, OpenHydro Site Developments, and Marine Current Turbines. Scotland's First Minister Alex Salmond said that 'These waters have been described as the Saudi Arabia of marine power and the wave and tidal projects unveiled today — exceeding the initial 700MW target capacity — underline the rich natural resources of the waters off Scotland.'"

Tidal generators don't create 'calm' zones, because tides aren't driven by a pushing force, rather by a pulling force (lunar gravitational pull), so water is merely dragged across/through a generator and continues to be dragged after it has passed the 'obstacle'.

Wave powered generators such as the Salter Duck did leave calm zones behind them as they absorbed the waves' vertical kinetic energy in long arrays strung out perpendicular to the direction of the waves' travel. However, these designs were dropped a

That WAS causing earthquakes? The nyt link didn't load for me even when I allowed scripts, I guess the NYT is dead to me. But I live near to The Geysers and they're still pumping shit into the ground, we're still more seismically active than without the shit-pumping, and they're still paying out claims for people with earthquake damage on Cobb mountain. I was relieved when they cancelled the plan to do their experimental drilling here, of the type that caused major seismic activity elsewhere. We really don'

Removing this energy from the ocean may cause an imbalance in the gravitational effects between the Earth and the Moon. Well, not imbalance, but rather a rebalance.

If we cause the Moon to move away from our planet, we lose both our astrodebris sweeper and more importantly our tide maker. Anthropogenic effects are real, and I'm not sure I'm happy to see the deliberate removal of energy from the ocean without further study on longterm planetary effects.

The electricity generated will power devices that shed heat, the heat adds to global warming, the global warming increases intensity of hurricanes and cyclones, the hurricanes and cyclones stir the oceans...no problem!

I wonder what it will be like for those humans, a million years from now, when they realize that the moon is crashing into the earth because their great-great-great-great-etc uncles needed more electricity to post on slashdot.

Temporarily, yes. But once the earth-moon system is tidally-locked, it will come back. Extracting tidal energy slows the earth's rotation and hastens the process.

Of course, a million years is slightly exaggerated. It's probably more than 30 billion years, without help, and of course the sun would vaporize us all long before then. We would have to build a lot of tidal generators to actually speed it up.

I'm confused about the motivations behind that "big question" post.Are you being serious but incredibly badly informed there, attempting a joke, or have some ulterior motive to attempt to influence the gullible?If you are being serious I suggest going down to the seaside and look at the waves hitting a big fucking cliff and consider how much energy is being tranferred there.If you are joking is it a dig at climate change being postulated to alter things on your perfect, unchanging 6000 year old earth? Thin

The force of gravity between the earth and the moon is roughly 2*10^20 newtons. Moving the moon 10 meters further from the earth would take over 10^13 Joules of energy (and that only accounts for the change in gravitational potential).

Furthermore, the rotation of the earth is already causing us to loose the moon at a rate of about 3 cm per year. If we were to reduce tide to the point where the ocean did not fluctuate at all, perhaps we wouldn't loose the moon in 1000000 years.

The force of gravity between the earth and the moon is roughly 2*10^20 newtons. Moving the moon 10 meters further from the earth would take over 10^13 Joules of energy

I think you're missing a "few" orders of magnitude there... 2*10^20 N over 10 meters is 2*10^21 J. 10^13 J is an absolutely wimpy amount of energy -- humanity consumes that much every couple of seconds.

Surely you mean move toward our planet? In any case, I imagine the energy required to shift the moons orbit any significant amount would be rather astronomical..... can someone be bothered calculating it out?

No moving away is correct the moon pulls the water the earth spins causing the rising water to move ahead of the moon which pulls back on the moon thus adding extra acceleration to the moon which causes it to move away.

The tidal bulge on the Earth actually drags on the moon and increases its orbital velocity. It does this because the rotation of the Earth drags the bulge ahead of the sub-lunar point. The gravitational field of the bulge attracts the moon so the earths rotation slows as the moons orbital velocity increases. Eventually we will be tidally locked like Pluto and Charon and tides will be much smaller.

My preferred solution is to dump a whole lot of nuclear waste on the far side of the moon and turn it into a bomb. I wanted my proposal implemented by 1999 but not enough people saw the gravity of the situation.

You calculated the kinetic energy of a mass of water moving forward at 30kph. In a wave water is not moving forward at the wave speed, but rather gently in an elliptic trajectory. I gather you used 10m as amplitude and not crest to through height.

The energy flux of waves is given by the formula which you can find on this wikipedia page [wikipedia.org]. A 20m (crest to through) wave with a period of 10s over a lenght of 50m gives you 20MW of wave energy. Still a lot, but almost 2 orders of magnitude less than 1GW.

What happens is that the moon pulls water towards itself (tides) then because the earth is spinning the tides are actually ahead of the moon which in turn pull the moon around the earth faster causing to get further away. So employing this would keep the moon where it is longer. Also the moon has a gyroscopic effect on earth and with out is earth's wobble would be more significant. So doing this would keep the moon around a little longer.

Greed, its all about greed. How can we get something for nothing. In this case energy. If any project steals energy from the waves, the whole eco-system and energy system is changed. What's at stake, fisheries, the gulf stream, the weather, whatever interacts with that energy system currently. I doubt that anyone has done extensive research on what the effects might be except on the bottom line. The ones that will make the money off this one are certainly selling it.

You're being funny, (I hope) but I might more seriously wonder about other side-effects. Way back when they were looking at a tidal energy project at the Bay of Fundy, when hydraulic modeling showed that harnessing that tidal energy would have the "side effect" of flooding Boston. I hope they've done such modeling for this. Now that I think of it, with greater computer power available, I wonder if they could examine variations on the Bay of Fundy project to find a way to get the energy without flooding B

Not only that but by converting gravitational potential energy into heat we create photons which transfer momentum to the moon and push it away faster. I propose that all future lunar landings be on the far side to compensate.

You laugh, but that happens with wind power in the states. You can build a wind farm of, say 100MW but the "greenies" will only allow you to put in trunking that handles 50MW because it might upset some frog species if you lay down more trunking.You can then increase your wind farm to 200MW, claim all the benefits for your State and lock down 3/4 of the blades (again, because the "greenies" won't let you increase the trunking off the wind farm).

Dounreay was more of a research location rather than a site for large scale power generation - the main nuclear power stations in Scotland are fairly close to cities (Edinburgh for Torness and Glasgow for Hunterston). It is a bit of a give away that it's about as far as you can get from London and still be on the mainland and have reasonable communication links.

Not really. We will be cheering on Algeria, Slovenia and USA in the world cup in June, and if that fails, we will have some more countries to cheer on. In the case of the USA, it wouldn't surpise me if there are more Scottish fans cheering on the team than natives.

I do wonder how ships disabled in storms can be handled in such a way to assure that wind farms are not destroyed. I live in an area where hurricanes strike quite frequently and even in calmer seas we end up with tankers stranded on our beaches all too often.

All other means of energy production will not be able to compete with a Liquid Fluorine Thorium Reactor. Maybe if they ever figure out fusion. But they'll probably have to go to the moon to mine Helium 3 to make that work and Obama is death on NASA.
http://en.wikipedia.org/wiki/LFTR [wikipedia.org]

WTF! Electricity was mentioned so of course somebody had to bring the crackpot nukes and the politics.At this small scale something cheap and simple beats big experimental nukes with technology twenty years behind South Africa, India and China any day. Give up on Oak Ridge, all they've been good for over the last twenty years is silly stories about how fly ash is supposedly nuclear waste even though it is less radioactive on average than seawater.If you want to be a nuke advocate and want to advocate thor

I'm not talking about a spill, i'm talking about a scare campaign.
The crap engineer was J. P. McBride at Oak Ridge labs who stepped outside of the field he knew to publish some alarmist crap in 1978. For some reason nobody since then has been able to find all the radioactive material that he insisted was so commonplace that it could be used by terrorists to build a nuclear bomb. It perpetuated furthur crap like the 2007 SciAm article "Coal Ash Is More Radioactive than Nuclear Waste" and a childish PR cam

It has already been documented that any undersea turbines will cause too much heat, crack the Earth's crust, and cause the polar ice caps to melt. We'd best keep the seaQuest DSV nearby to stop it when it happens!